Viewing archive of Friday, 30 May 2025

Daily bulletin on solar and geomagnetic activity from the SIDC

Issued: 2025 May 30 1241 UTC

SIDC Forecast

Solar flares

M-class flares expected (probability >=50%)

Geomagnetism

Moderate (ISES: Major) magstorm expected (A>=50 or K=6)

Solar protons

Quiet

	10cm flux	Ap
30 May 2025	149	047
31 May 2025	153	029
01 Jun 2025	155	027

Solar Active Regions and flaring

Solar flaring activity was moderate over the past 24 hours. The largest flare was an M3.4 flare peaking on May 30 at 06:13 UTC, which was produced by SIDC Sunspot Group 469 (NOAA Active Region 4100, magnetic type Beta-Gamma). This region was responsible for most of the flaring activity. Returning region SIDC Sunspot group 490 and SIDC Sunspot Group 510 (NOAA Active Region 4101) showed flux emergence and produced C-class flaring. SIDC Sunspot group 508 (NOAA Active region 4099, magnetic type Beta-Delta) was stable. There were 7 numbered sunspot groups on the disk over the past 24 hours, the rest of these regions were simple and mostly quiet. The solar flaring activity is expected to be moderate over the next 24 hours, with M-class flares expected and a chance for X-class flares.

Coronal mass ejections

A dimming was observed on disk associated with the M3.4 flare. An associated Coronal Mass Ejections (CME), first observed at 07:12 UTC May 30, is being analysed. An initial analysis suggests an Earth directed component is likely.

Coronal holes

An extended equatorial coronal hole (combined SIDC Coronal Hole 116 and 112) continues to transit the central meridian since May 26.

Solar wind

The solar wind conditions reflected the ongoing impact of the high-speed stream associated with the large equatorial coronal hole that first began to cross the central meridian on May 26. The solar wind speed ranged between 650 and 830 km/s. The interplanetary magnetic then decreased from 12 nT to values near 7nT. Bz ranged between -11nT and 10nT. The interplanetary magnetic field phi angle was mostly in the negative sector. Further enhanced solar wind conditions are expected over the next 24 hours due to the ongoing high-speed stream.

Geomagnetism

Geomagnetic conditions reached moderate storm levels globally (Kp 6) between 12:00 UTC and 21:00 UTC on May 29. This is due to the ongoing high-speed stream associated with the negative polarity coronal hole that began crossing the central meridian on May 26 (SIDC Coronal Hole 116 and 112). Locally, only moderate storm conditions were observed (K Bel 5). The conditions then reduced and are at unsettled to active levels at the end of the period. Active to minor storm conditions expected to continue over the next 24 hours, with isolated periods of moderate storm conditions possible, due to the ongoing impact of the high-speed stream.

Proton flux levels

The greater than 10 MeV proton flux was below the 10 pfu threshold over the past 24 hours. It is expected to remain below this threshold level over the next 24 hours.

Electron fluxes at geostationary orbit

The greater than 2 MeV electron flux measured by GOES 18 was briefly above the 1000 pfu threshold. The greater than 2 MeV electron flux is expected to again exceed the 1000 pfu threshold over the next 24 hours. The 24-hour electron fluence was at normal levels and is expected to be a normal to moderate levels over the next 24 hours.

Today's estimated international sunspot number (ISN): 124, based on 20 stations.

Solar indices for 29 May 2025

Wolf number Catania	102
10cm solar flux	145
AK Chambon La Forêt	057
AK Wingst	///
Estimated Ap	052
Estimated international sunspot number	106 - Based on 19 stations

Noticeable events summary

Provided by the Solar Influences Data analysis Center© - SIDC - Processed by SpaceWeatherLive

All times in UTC

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